VARLEY, CROMWELL FLEETWOOD (1828–1883), electrical engineer, son of Cornelius Varley [q. v.], watercolour painter, and nephew of John Varley [q. v.], was born at Kentish Town, London, on 6 April 1828, and was named after two of his ancestors, Oliver Cromwell and General Fleetwood. Andrew Pritchard [q. v.] was his first cousin. He was educated at St. Saviour's, Southwark, where he was a schoolfellow of Sir Sydney Waterlow. After leaving school he studied telegraphy, and, through the influence of William Fothergill Cooke [q. v.], was engaged in 1846 by the Electric and International Telegraph Company, with whom he remained until the acquisition of the telegraphs by the government in 1868, when he retired into private lite, spending his time in bringing out new inventions. During the early part of his business career he attended lectures at the London Mechanics' Institute, and, in connection with his brother Theophilus, he inaugurated the chemistry class there.

The first improvement he introduced in telegraphy was the 'killing' of the wire by giving it a slight permanent elongation, which breaks out the bad places and removes the objectionable springiness which results from the drawing process. Next he devised a method of localising the faults in submarine cables, so that they could be easily found and remedied. On 16 Feb. 1854 he patented his double current key and relay (No. 371), by which it became possible to telegraph from London to Edinburgh direct; then came his polarised relay, his English patent anticipating by two days the date of Siemens's German patent for a like invention. His next improvement was the translating system for use in connection with the cables of the Dutch lines, and by its means messages were sent direct from England to St. Petersburg with the aid of two intermediate relays. In 1870 he patented an instrument, which he called a cymaphen, for the transmission of audible signals, and it is claimed for him that it contains the essentials of the modern telephone. However that may be, a year before the date of the Bell patent—namely, in 1870—music was transmitted by this instrument from the Canterbury Music-hall in Westminster Bridge Road to the Queen's Theatre in Long Acre over an ordinary telegraph wire with complete success.

Varley's name is probably chiefly remembered in connection with the Atlantic cable. The first cable, laid in August 1858, was a failure. Before the project for the second cable was published, it was referred to a committee, consisting of Robert Stephenson, Sir William Fairbairn, and Varley, to report as to its capabilities and the probability of its success. It was at this time that Varley conceived the idea of making an artificial line, composed of resistances and condensers, which should exactly represent the working conditions of a submarine cable. The resistances corresponded to the copper conductor, while the condensers reproduced the induction which takes place between the two sides of the dielectric, and thus by the aid of the artificial line it became possible to predicate the speed of signalling through any proposed cable, and a subject which up to that time had been much obscured was placed upon a scientific basis. As a result of his experiments he offered to guarantee that the proposed cable should transmit twelve words a minute, a rate of speed which in practice was soon exceeded. He afterwards, in 1867, read a paper at the Royal Institution (Proceedings, 1869, pp. 45-59) 'On the Atlantic Telegraph,' when his lucid explanations and practical demonstrations contributed greatly to the restoration of public confidence in Atlantic telegraphy, and to the renewal of that most important enterprise.

In 1865 he was elected a member of the Institution of Civil Engineers, and on 8 June 1871 a fellow of the Royal Society. He likewise took a great interest in the establishment of the Society of Telegraph Engineers in 1871, and was a member of the council. His papers in the 'Philosophical Transactions,' the 'Reports of the British Association,' and the 'Electrician' are all connected with the subjects of electricity and telegraphic communication. Like his uncle John, Varley was a rather credulous investigator of spiritualistic and other occult 'phenomena.' He died at Cromwell House, Bexley Heath, Kent, on 2 Sept. 1883, and was buried at Christ Church, Bexley, on 6 Sept. His second wife, whom he married on 11 Jan. 1877, was Jesse, daughter of Captain Charles Smith of Forres, Scotland. By a former wife, from whom he was divorced, he left two sons and two daughters. His two brothers, Frederick Henry Varley and Samuel Alfred Varley, were also improvers and inventors in connection with telegraphy.